The minority investment was made through a unit and is one of various in the “broader energy sector,” Reliance said on Thursday without disclosing the size of the investment.

Terra Power, based in Washington, is designing a nuclear reactor that uses low-enriched uranium and produces less waste.

The reactors need uranium to start up and can “run for decades on depleted uranium” without enrichment or reprocessing, Terra Power said on its website.

Gates, 56, ranked as the world’s second-richest man in March by Forbes magazine, visited China earlier this month to promote a new technology for fourth-generation nuclear reactors developed by Terra Power.

Development of Terra Power’s “travelling-wave reactor” may require an investment of $1 billion in the next five years and they will cost “billions” to build, according to Gates, who spoke to China National Nuclear Corp. during his visit on Dec 7. The “new approach” to nuclear power is still at an early stage and its adoption won’t move fast, he added.